The instant invention presents a revolutionary concept in window treatment that provides a high degree of light control, while at the same time providing a significantly higher level of insulation and lower shading coefficient than previously available in energy efficient window treatments. The instant invention's "Venetian Blind" window treatment concept combines the functional advantages of providing light-filtering and room-darkening effects together with insulating and heat-blocking effects, all within a single pleated fabric shade format. It relies upon the recent development of new processes for applying high-remelt-temperature copolymers and powdered metal-loaded untraviolet (UV) -curable resins to polyester fabrics which are shaped into a novel mechanical configuration that results in a window shade system having directional and variable light transmissivity. A novel mechanical design for varying the light transmissivity involves surface modification of a pleated fabric and reflective slat articulation to create trapped air cavities or sleeves within the shade invention. This significantly reduces both convective and radiant heat transfer within and through the invention. The resulting window treatment system, in combination with multi-layer fenestration systems, yields thermal resistance values up to R 6.0.
Before the instant invention, numerous attempts had been made to selectively, incorporate what are inherent characteristics of the instant invention, namely, variable light transmissivity and variable insulative/heat-reflective properties. Some of these prior inventions also used methods for the manufacture of their novel devices. One of the most important forerunners of the "honeycomb shade" art was Rasmussen who, with U.S. Pat. No. 4,019,554 in 1977, set the stage in "honeycomb shade" devices for years to come. Rasmussen developed a thermal insulating curtain, for use especially in greenhouses, by adapting the slat array of the common Venetian Blind with parallel, interconnecting foldable fabric nettings, to obtain a rectilinear curtain comprised of two opposing fabric surfaces partitioned by an array of parallel slats. The Rasmussen invention is retracted by rolling the parallel fabric sheets on a cylindrical roller. Alternatively, if the slats are rigid enough, they may be drawn upward, one slat snuggly residing colinearly with the slat immediately above it and the fabric, pleated as it were, folding and overhanging the slats. The most significant disadvantage to the Rasmussen device is that light transmissivity depends upon the translucency or opacity of the interconnecting fabric. The slats are provided only for rigidity and to form the parallel "columns" of air which lend to the invention its insulative properties. As with light transmission, the fully raised or fully lowered position of the Rasmussen invention provides only a noninsulative or fully insulative character, respectively. Further, in the roll-up version, the rear panel is collected slightly ahead of the front panel; therefore, a tilting of the slats, one in respect of the others, takes place. This characteristic is a result of the fact that the rear panel, because of the collector (roller) geometry, is taken up a bit more rapidly than the front panel. Thus, the tilting of the slats is a natural resultant of rolling up the blind, rather than a design element provided by the inventor.
Notwithstanding the disclosures of Rasmussen, Anderson was issued U.S. Pat. No. 4,677,013 in 1987 for the method of forming a honeycomb structure that physically varied little from the Rasmussen concept. However, Anderson devised a novel means for forming his structure from a continuous length of foldable material that is folded into a Z-configuration and stacked in layers which are then adhered together. Additionally, U.S. Pat. No. 4,685,986 was issued to Anderson in 1987 for yet another method of making honeycomb structure by joining, two pleated sheets of material. The honeycomb structure is formed of two continuous lengths of pleated materials, secured together intermediate the pleats. Each length of pleated material defines one side of the honeycomb structure; and the two continuous lengths are secured together by feeding them longitudinally (lengthwise) toward each other. At their juncture, the confluent pleats are joined together at what may be defined as the "troughs" of the pleats. Relative to the materials disclosed in both of the Anderson inventions, it can be said that the inventor abhored the type of device that allows material to "hang out" when the slats are retracted for stowage or full daylight transmission. To this end, he discloses the use of non-woven fibers of polyester or woven materials of plastic, or materials combining textiles fibers plus plastic. Also revealed for usage are laminates in which bleed-through of adhesive can be controlled. Most importantly, in Anderson '986, it is indicated that the two pieces of material forming the opposite faces (of the cells) may be secured together by separate strip materials extending longitudinally between the cells. This arrangement is said to have the advantage that strip materials can be chosen so as to permit a wider choice of adhesives. Unfortunately, Anderson discloses this in '986, but not '013. The invention of, '986, consists essentially of the overlapping of two pleated fabrics at their cojoining verticles, longitudinally. Therefore, the strip to which the inventor referred, was initially quite narrow. Anderson did not apply this concept to the honeycomb structure of '013, which more closely resembles the Rasmussen invention. Thus, it may be said that Anderson did not contemplate the use of rigid slats to differentiate between the insulative air columns of his shade; but rather, only the overlapping material with adhesive therebetween (which would provide a modicum of stiffening) was employed.
Irrespective of the variation in both product and the manufacture of product of the extant art, none are seen to have provided the novel shade means hereinafter disclosed by the instant inventors, with its broad-spectrum light transmission, insulative/heat blocking characteristics. Most noticeable in the present state of the art insulative shades is the absence of an ability to vary such characteristics.